The Center for Research on Health Care (CRHC) Data Center at the University of Pittsburgh proposes to coordinate data collection and management, study monitoring, training and quality control, and shared research services across sites as the Data Coordinating Center (DCC) for the HALT-Polycystic Kidney Disease (PKD) Trials. The HALT-PKD trials comprise 2 randomized clinical trials conducted at 7 clinical sites supported by a central imaging facility (also at the Univ of Pittsburgh), a drug distribution center, 2 central laboratories, and 3 outside contractors. The Consortium is governed by a Steering Committee with help from 9 subcommittees and is overseen by an External Advisory Committee/Data Safety and Monitoring Board. Study data and biospecimens are deposited in 3 NIDDK repositories. In Study A, the effect of study medication on structural progression at 2 levels of BP control is assessed using a 2x2 factorial design. Study B compares ACE-I/ARB combination therapy with ACE-I monotherapy on the time to a 50% reduction of baseline estimated GFR, ESRD or death. The CRHC Data Center currently coordinates the CRISP II cohort (Consortium of Radiologic Imaging Studies of PKD), and we will apply our expertise in PKD and data management and analysis to: 1) develop a Web-based data management system that incorporates data tracking, entry, quality control, saftey monitoring, and report generation;2) organize trial communications, support recruitment and retention at each site, and coordinate and monitor the transfer of data, images, and biospecimens;and 3) plan and conduct statistical analyses to support the aims of each study. Co-locating the DCC for CRISP II and HALT-PKD will enhance the efficiency of data management, pooling, and analyses that could lead to new hypotheses and spin-off study designs. Following the seamless transition of the CRISP II DCC to Pittsburgh, we rapidly developed a Web-based data management and entry system and will apply our prior experience in moving an existing DCC for an ongoing multisite trial to minimize downtime for HALT-PKD. The CRHC Data Center has PhD-level statisticians with expertise needed for this effort, including genetics and longitudinal analyses of correlated data. Data Center personnel also bring expertise in customized form design, on-demand study progress reporting, and site staff training. We are dedicated to completing our work in a timely fashion and respecting the needs of clinical Pis and HALT team.